Various additives are used in ice cream type articles in order to impart a smooth structure and a feel of body. Most of the additives are hydrophilic polysaccharides such as guar gum, locust bean gum, carageenan, pectin, etc. These additives, however, have a low solubility in the mouth and hence are liable to give a so-called pasty feel.
There are also cases where microcrystalline cellulose was added into ice cream type articles in order to impart a plain texture and heat shock resistance (a function of suppressing the growth of ice crystals caused by a temperature rise or drop during storage) (JP-A-54-54169, JP-A-54-55762 and JP-A-54-157875). Such techniques were used to impart a plain texture and heat shock resistance without deterioration of other performance characteristics by replacing a portion or the whole of a conventional additive (a hydrophilic polysaccharide) with a certain kind of microcrystalline cellulose complex.
The effect of the replacement, however, was not always sufficient.
That is, when a complex containing carageenan or xanthan gum is used in place of the above-mentioned hydrophilic polysaccharide, a relatively plain texture can be obtained. But when the complex is used in combination with the hydrophilic polysaccharide, a heavy texture is given. When guar gum or locust bean gum is blended, a stable suspension is formed, for example, by pre-dispersion with a mixer for home use for 3 minutes followed by one-pass dispersing treatment at a pressure of 24.52 MPa (250 kg/cm2). However, in the case of treatment with a high-pressure homogenizer used for industrial production, the blending of guar gum or locust bean gum tends to cause blocking, so that the blending is disadvantageous in practice in the production of ice cream.
JP-A-4-502409 discloses that an aggregate comprising microcrystalline cellulose and galactomannan gum is effective as a non-nutritive fat-like bulking agent for food such as ice cream. This material is characterized in that when dispersed in water, it is not substantially disintegrated and retains the shape of dry powder particles, i.e., their spherical shape. This characteristic is the essence of the invention disclosed in the above reference. The above reference describes the following: for the modification of the surface of the aggregate comprising microcrystalline cellulose and galactomannan gum, xanthan gum or maltodextrin is blended to be adsorbed on the surface of the aggregate, whereby a function as a stabilizer in food is imparted to the aggregate and the taste is improved. Also in this case, the aggregate having the modified surface is not substantially disintegrated in water.
The above reference describes the fact that particularly when the gum (guar gum) content is approximately 1 to 15%, the spherical particles substantially retain their original shape before dispersion in water and have a higher shear resistance. The above reference also describes the case where the aggregate particles can be used after their forced conversion to a very fine fibrous material, only at a gum content of approximately 15 to 40% and under high-energy shearing (for example, treatment with a high-pressure homogenizer at a pressure of 41.37 MPa (422 kg/cm2)) conditions. This fact means that the above-mentioned aggregate particles having a gum content of approximately 1 to 15% are not reduced in particle size even under such high-energy shearing conditions.
The above invention cannot solve the following existing problems. When the gum content is high, the aggregate particles give a pasty feel when incorporated into food, in particular, an ice cream type article, even if they are used in the form of either spherical particles or a fibrous material. On the other hand, when the gum content is low (20% or less), the particles are not finely dispersed, resulting in a decreased feel of body and a low heat shock resistance. There is also the following problem. When the size of the dry powder particles of the above invention is large, the dry powder particles are not reduced in particle size by pre-dispersion treatment. Therefore, when a piston type high-pressure homogenizer is used for the conventional production of an ice cream type article, stable homogenization of a liquid raw material for ice cream without pressure variation is difficult and blocking is caused in some cases.
Moreover, in recent years, the contribution of food to, for example, the suppression of excessive energy intake and the improvement of bowel and stomach conditions has been extensively investigated in order to prevent recent lifestyle-induced diseases such as diabetes, and various low-caloric or noncaloric foods and dietary fiber fortified foods have been developed. The point of the development has been that the changes of the appearance, state, texture and taste caused by enrichment with dietary fiber, in particular, water-insoluble dietary fiber which is said to be very effective as a substitute, are improved while reducing the blending amount of fat and oil, i.e., a main cause for energy, according to need. Many foods, however, have not been improved so as to be “delicious food low in calories and enriched with water-insoluble dietary fiber”.
As cellulosic materials among materials for supplementing the body and texture of low fat food, i.e., so-called fat replacer, there is the material formerly disclosed in JP-B-39-20181 as well as the materials disclosed in JP-A-4-507348, JP-B-6-11793, etc. These materials are highly effective in improving the body, appearance and the like but cannot supplement “substance” due to oil.